In many instances the unique or distinguishable identification of an individual entity, such as an individual animal, person, or item is required. Furthermore, in many such instances such identification must be easily visible, observable, or accessible. For instance, in the sale of cattle at auction, unique or distinguishable identification of the animal is needed to verify, among other things, the country of origin of the animal. Such identification must be readily visible, observable, or accessible, yet must be verifiable or certifiable.
Prior art methods for identifying an individual steer at auction include plastic ear tags, electronic ear tags, and implanted or ingested electronic tags. Prior art external tags are undesirable due to the ease with which they can be tampered with or switched from animal to animal. Prior art implanted or ingested electronic tags are limited by their need to transmit a stream of data (e.g. their unique identification numbers) to the outside world. This requires relatively high power consumption and relatively expensive transmitter and receiver hardware.